Can a population evolve to survive?

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: Here you will find clear descriptions of what you just saw, how they know what they said they knew, why they know it to be trustworthy information. Finally we will ask the question, "So what!" and explore why the information is important.

WHAT do we know?

In this clip from the 2005 presentation “Impacts of Changes in Extreme Weather and Climate on Wild Plants and Animals,” biologist Camille Parmesan explains how warming climates may be leading to a change in genetic ratios in populations of Edith’s Checkerspot Butterfly. In populations that have successfully settled in new areas (dispersers), more of the butterflies had high ATP and large flight muscles than did populations that had lived in the same area for a long period of time. In response to a question from the audience, Dr. Parmesan explains that although populations may evolve to be better dispersers over the short term, because dispersers have low reproductive rates, the ratio of dispersers to sedentary individuals will likely shift again once a new population has been established.

HOW do we know?

Population genetics are studied by observing visible physical characteristics of individuals in a population or by analyzing cells to search for a specific genetic sequence.

WHY can this be trusted?

Studies such as Dr. Parmesan’s require on-the-ground observation and, sometimes, capture of butterflies in remote mountain locations. Because she needed to be able to compare her own results with previous observations of populations similar to or the same as those studied by others, Dr. Parmesan’s ground study locations were determined by where she had data from previous experiments.

SO WHAT?

Scientific data suggests that the climate is warming.  In both apparent and subtle ways, these changes in average temperature will impact where certain species are able to survive.  Studies such as Dr. Parmesan’s suggest that some species may be able to adapt or evolve on a population level in order to survive these changes.  Understanding which species are likely to be able to survive on their own and which are at risk for extinction is important for scientists and decision-makers who want to preserve biodiversity.

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Further Reading
Further Reading: 

Parmesan, C., T.L. Root & M. Willig.  Impacts of extreme weather and climate on terrestrial biota.  (2000) Bull. American Meteorological Soc.  81: 443-450.

A complete video of Dr. Parmesan's public lecture on this same topic is available on agci.org.